1. Field of the Invention
The invention concerns soil watering and covers several stand-alone mechanical devices, which have in common one original characteristic that optimizes a controlled watering function.
2. Description of Related Art
Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
In many regions, watering cultivated plots is essential. To do so, one or more watering devices, generally sprinklers or drop watering systems, are connected to a source of water under pressure. Their water intake is automated by means of an electromagnetic valve, which is controlled by an electronic or electromechanical programming device that determines the successive moments when watering starts and stops. The results can never be entirely satisfactory because even users who are entirely familiar with their terrain cannot keep track of all the different parameters that govern the behavior of soils and plants with respect to water. Moreover, these installations are costly, and they all depend on a source of electrical power on the spot, a constraint that it would be useful to remove.
Controlled watering systems use several different models of electromagnetic valves that are available over the counter. Most of these models comprise a solenoid capable of bringing, into two stable predetermined positions, a ferromagnetic core fixed to the control nozzle of a hydraulic relay, which is activated by the pressure of the water and capable of causing the valve to open and close. Both core and nozzle are enclosed in an impermeable sleeve which runs through the solenoid. Experience has shown that this type of electromagnetic valve is particularly reliable.
The behavior with respect to water of the surface soil (less than 30 cm or so in depth) in which most plants grow depends on many different parameters, especially the soil's permeability, capillarity, water retention capacity, evaporation coefficient, exposure to dominant winds and the nature of the soil layers beneath. Concerning the plants, it must be remembered that watering in full sunlight can harm the leaves (magnifying effect of water droplets), and also causes immediate water losses of up to 70% through evaporation. These parameters are well known to specialists, but have not yet been taken into consideration by those with an interest in the construction of purely mechanical systems (i.e., which do not require any electrical power) for automatic controlled watering.
In the French patent No 78.04479 by Delattre, a stand-alone mechanical system is described, comprising a deep pan with perforated sides, mounted on a bistable balance arm, filled with a sample of soil and plants and balanced by a counterweight. The tipping motion of the pan, as it gains or loses weight with watering or evaporation and drainage, directly controls a mechanical valve. This heavy, cumbersome system is representative of most of the parameters concerned and can generate sufficient force to control the valve directly. However, because the plants are continually growing, it is not particularly reliable. It does not take sunlight into account and can neither change the duration of watering or the interval between two consecutive periods of watering.
In the French patent No 79.16748 by Brossard, a stand-alone mechanical controlled watering device is described, comprising a mechanical valve which is directly controlled by a pivoting arm, with a perforated basket containing an absorbent body at one end and a counterweight at the other end. Although this is a simple and realistic device, direct control of the mechanical valve, when subjected to the pressure of water, by means of the oscillating motion of the balance arm alone, requires a relatively high bearing force that is not available. Moreover, there is no means of regulating the duration and/or the intervals between watering, and exposure to sunlight is not taken into account.
In the French patent No 1.300.228 by Castelli, a stand-alone mechanical controlled watering device is described, comprising a container that can be filled by rainwater or irrigation water, associated with a pivoting float that directly controls a mechanical valve. This mechanical device only takes evaporation into account and is therefore unsuited to the problem addressed. Moreover, as in the previous cases, there is no means of regulating the duration and/or the intervals between watering, and exposure to sunlight is not taken into account.
In the French patent No 1.380.569 by Raucourt, a stand-alone mechanical controlled watering device is described, comprising a flap valve which is directly controlled by a lever arm. This is mounted onto a bistable pivot, which has a container filled with soil on one end and a counterweight on the other. As the container is not perforated, this device—like the previous one—is only representative of soil evaporation. Moreover, there is no means of regulating the duration and/or the intervals between watering, and exposure to sunlight is not taken into account. The flap valve needs considerable actuating force which the tipping of the balance arm alone is unable to provide.
Each of these known mechanical devices for controlled watering comprise a simulating member that reproduces various parameters governing the behavior of soils with respect to water, but these parameters are generally too few in number. The devices have no means for regulating the duration and/or intervals between watering or for taking exposure to sunlight into account. In addition, the effectiveness of the different means used to trigger the opening and closing of the valve is open to doubt, because of the amount of effort required.
The overall object of the invention is a stand-alone mechanical controlled watering device which can be actuated by a force of very low amplitude.
The first specific object of the invention is a stand-alone mechanical controlled watering device which enables the amount of water actually distributed to be continuously adapted to the actual needs of the plot and/or the different planters or pots to be watered.
The second specific object of the invention is a stand-alone mechanical controlled watering device which is at once economical, simple to manufacture and easy to use.
The third specific object of the invention is a stand-alone mechanical controlled watering device that comprises a simple, lightweight and easily handled soil-simulating member that takes into account the broadest possible range of parameters governing the behavior of soils with respect to water.
The fourth specific object of the invention is a stand-alone mechanical controlled watering device which, by means of a simple adjustment, can change the interval between two watering periods, insofar as the interval will depend on the condition of the soil, by simultaneously adjusting the characteristics, capillarity, permeability and water retention capacity of the simulating member in accordance with the characteristics of the soil concerned.
The fifth specific object of the invention is a stand-alone mechanical controlled watering device which, by means of another simple adjustment, can determine the duration of watering, insofar as the duration will depend on the condition of the soil.
The sixth specific object of the invention is a stand-alone mechanical controlled watering device which can shut off any further watering whenever sunlight becomes too strong.
The seventh specific object of the invention is a second stand-alone mechanical controlled watering device which is derived from the first and is specially adapted for drop watering of indoor plants in pots or planters.
The eighth specific object of the invention is a third stand-alone mechanical controlled watering device which is suited to every type of watering, including sprinkling or drop watering.